Series spring-suspension system



Oct. 26 1926.

F. L. O. WADSWORTH SERIES SPRING SUSPENSION SYSTEM Filed Dec. 18, 1922 2 Sheets-Sheet 1 F. L. O. WADSWORTH SERIES SPRING SUSPENSION SYSTEM Filed Dec. 18, 1922 2 Sheets-Sheet 2 Oct. 26

. UNETED STATES FRANK L. O. VIIADSWORTH, OF PITTSBURGH, I'ENNSYLVANIA.

SERIES SPRING-SUSPENSION SYSTEM.

Application filed December 18, 1922.

hily inyention relates to improvements in the type of spring; suspension system ,which comprise a plurality of elastic or resilient supports that are operatively conjoined or coupled in permanent series relationship and are subjected to superimposed or progressively increased tlexural strains whenever the system is subjected to either compression or expansion stresses. The present application is, in part, a continuation of my endingapplications Ser. Nos. @0256 and 591,708 tiled respectively July 20, 1920, and Oct. 2, 1922; and the general characteristics and advantages of this type of shock absorber construction are set forth in these earlier disclosures.

The specific object of my present improvements is to provide a simple and citicient combination of series-connected leaf springs which resembles in general form and outline either an ordinary lull elliptic, or a three-quarter elliptic, spring support; but which is adapted, not only to elastically cushion and absorb the edects of an increased load stress i. e., of compressive shoelr but also to elastically resist and quickly check any rebound, or separation of the spring; supported parts, beyond normal load position.

Another particular purpose of these improvements the provision of a self contained supplemental leaf spring unit which may be interposed between the end, or ends, of an ordinary leaf spring; member and that part of the vehicle to which said end, or ends, is usually connected, without any sensible modification or alteration oi the other parts of the suspension organization; and without substantially increasing the bulk or weight oi": the stands forms of spring support with which such a unit may be used.

further specific object of my improve ments is to provide a supplemental spring unit which can be utilised, in conjunction with either a cross leaf spring, or a side leaf spring, to prevent any sensible end sway axial oscillation in the plane of the suspension system; and which will therei orewhen applied to a cross leaf spring arrest any side swing; or lateral displacement of the vehicle body or tonneau with re spectto its axle or running gear supports.

(.lther special features and advantages o'l various forms oi? my improved supplemental leaf spring constructionas used in Serial No. 607,495.

combination with particular types oi main spring supports-will be readily recognized and appreciated, by those skilled in this art, after an examination of the illustrative embodiments of my invention which are depicted in the accompanying drawings and are hereinafter descril ed. In these drawings:

Fig. 1 is a front elevation of one of my nnproved series spring suspension sy tems as applied to the front axle mounting of a Ford car; Fig. 2 a similar view of the same organization with the parts thereof in the position of extreme rebound; Fig. 3 is a rear elevation of another form of my in'iprovements applied to the rear aide sup port of this type of car; Fi lis a detail view of a modified term of guide link which may be used in conjunction with either of the foregoing constructions; 5 is an enlarged cross section through a modified form 01" supplemental spring]; elen'ient; F 6 is a side view-partially in section-pt a third exeinplification oi my invention; Fig. 7 is another side view of a fourth exen'iplification; Fig. 8 is an enlarged elevation of a part of the organization shown in Fig. 6 but with the parts oil the system in an expanded position; Fig. 9 is a cross section entire plane.99 oi Figs. 7 and 6; Fig. 10 illustrates still another se'ies spring sus pension which partially embodies iny pres ent improvements; Fig. 11 is a somewhat enlarged sectional elevation of a portion of the complete system shown in Fig. 9 with the parts of this system in a compressed position; Fig. 12 is a cross section on the plane 1212 of Figs. 11 and 13; and Fig. 13 is a view like that of l 10, but with the parts in the positions assiuned under an expansion stress.

In the form of construction shown in Figs. 1 and :2 the cross leait main spring 1 is rigidly secured at its center to the body of the car; and its outer eye ends-which are ordinarily suspended on the axle perches by swinging shackle linlrs are elastically supported on the extremities oi two reversely turned supplemental leaf springs 33 that are bolted, at their adjacent ends, to short L-shaped levers l, These unitary leversprinp; members are pivotally mounted on a U-shapcd bracket 6 which is rigidly bolted to the axle 2; and the points oi? pivotal support, 5*5, are considerably offset to one Ill side of the longitudinal axes of the springs 33 for a purpose which will be presently explained. The outer ends of the levers t are operatively connected to the opposing central part of the main'spring body assemblageby the flexible straps '?-7 and the clamps 88-10. The outer conjoined e:;- tremities oi the main spring 1 and the supplemental springs 3 3, are preferably con nected to the 1GVG1.'S axle perches 11-11 by means of the guide links 18, 1-3, which are so proportioned and positioned that their ends travel in an are that is substantially coincident'l or a considerable part of its lengthwith the free path oi move ment of the conjoined spring eyes as the spring members are oscillated and increasingly fleXedi. e., straightened outby the relative movements'of the body and axle part-s toward or away from each other. Th

axle bracket 6 is also provided with a bumper 14 of rubber or other suitable material, which will engage with the main spring body clamp 10 when the system is subjected to abnormal compression, and will thus serve to prevent the main spring from coming into direct contact'with the arms 01 the said bracket. But neither the guide links 13, 13 or the bumper 1% are essential to the proper functional action of the series connected spring combination which operates as follows:

In the normal load position of the partsshown in Fig. 1the lever frames 1, 1-, rest on the axle '2, and the flexible st up connections, 7 7, are so adjusted in length as to free from slack. Under these conditions the normal load on the body frame is trans mitted through the flexible main spring 1, to the ends of the sup alemcntal springs 3, 3, and these seriesconnected springs are cooperatively flexed-in substantie lly the same manner as the two sides of a :tull elliptic elastic strain springare fleXed -until the therein balances the imposed s.

supplemental spring; elements being; L ably of such initial as to maintain the parts in static eq uflllllfl when the guide links 13 13 (if used) are slightly in clined downwardly. hen the system is subjected to compression shoc bo y and axle parts are forced towaro each ct and the series connected main and supp mental springs are then simult neously a...)- jected to progressivelyincreased lieXures which flattens them out to the. form indicated by the dotted lines o-c-c of Fig. 1until the augmented elastic resistances of these elements checks the approach movement. During this phase of the operation the connections 7-7 are loose and inactive; but as soon as the parts again re urn or recoi normal load posit on. the said connections are subiected to tension: and it the body and axle parts rebound or separate beyond tiis positioni. e. move toward the 8X- panded or supernormal positions 7, 7", of Fig.

the pull of these tensioned straps positively rotate the levers, 4;, a, on their oliset axle supports and longitudinal movements of the sup- 1 mental spring ends-as these auxiliary uspension elements swing upward and outwarc o the oilset axes, 5, 5, and straighten out under the effect of increased tlexurecoincide with the normal fiexural movements of the adjacent ends of the main spring; 1 as the latter is also moved upward and'flated out; the end connected system of 1; its. 13-3 is thus enabled to actin both rebound and compression like a very lexible full elliptic spring.

The construction illustrated in Fig. 3 is alogous to that shown in Figs. 1 and 2; and difiers from the latter only in such details as are attendant on its use in conjunction with the rear axle mounting of the car. in this utilization of my improved suspension system the supplemental spring-lever units 8 l are pivotally mounted, at 5"--5 on a saddle member 6 which rests upon and is bolted to, the top of the differential gear case of the rear aXle housing; and these levers are coupled to the superimposed body member by the collapsible and adjustable link and turn buckle connections, T W, and the pint-1e blocks 88?-. The outer connected ends of the main and supplemental springs 1-3 are preferably .q uided in their curved path of movement by suitable links 13*.13 which are rockably supported on flexible brackets 1-516 that are bolted to. the brake drum cases at the ends of the rear axle housing 2. The operation. of this rear axle spring system is the same that of the front axle spring; support previously described and does not theretore require further explanation. The full lines of show the relative positions of the parts when the system is subjected to normal load stress: and the dotted line positions c-c 0 and r1"-r. at the right and left sides of the figure, diagrammatically. illustrate the positions. and the concurrently increased liexures, of the series connected main and supplemental springs when the system is subjected to increased kinetic load and to rebound or expansion stresses respectively.

lVhen the organizations shown in Figs. 1, 2 and S are used as cross leaf spring supports-as here shown-all lateral or sidewise sway of the body and n1 ain spring with respect to the running gear, is positively prevented by the longitudinal rigidity of the supplemental springdever units 3-el- (or 3 and the axially fixed pintle connections between theseparts and the main spring and axle members. When the spring connected members are sul'i ieetel to rebound or expansion stresses the transverse bracing action of the increasingly flexed and stiffened suspension spring members, (34s") is further supplemented by the symmetrically opposed tensions in the oppositely inclined connections 7 (or l -7 that exert a continuously increasing restraint on any sidewise displacement of the expanding members. If the end guide links 13 (or 13) are employed these members cooperate with the supplemental spring elements 3, 4, and? (or 34 7 in always maintaining the body in centered relationship on the running gear supports; and also serve to prevent any transverse or fore and aft displacement or twisting, of the cues of the suspension springs with relation to the axle perch members 11 (or 16). These guide links fu ther serve to limit and prevent any very extreme or excessive rebound or expansion of he suspension systems, because y displacement of the parts beyond the positions r-r (Fig. 2 or 3) involves a sensible inoven'ien't of the ends of the said links away from the normal paths of movement of the connectwl leaf spring eyes; and the further separation of the body and axle members thereafter powerfully resisted and almost immediately arrested by the direct endwise pull of the rigid connections 18 (or 13) on the vertically flexible, but longitudinally stiff sides of the main spring member 1.

The purpose of offsetting the pivotal supports 5 (or 5 with respect to the 101. itudinal axes of the supplemental. springs or 3) is to increase the range or er tent of substantial coincidence between the normal. l'lexural movements of the series connected eye ends of the spring: units 1 and 3 (or 1-3) and to likewise increase the possible range of vertical swinging movement of the conjoined guide links 13 (or 13). This range of guide link movement may be still further extended, if desired, by making use either .of the sprin bracket 1.6 shown in Fig. 3), or of the transversely rigid. but longitudinally flexible SQllllll shackle links 13, one of which is shown in 4:, The emplovinent of either one of the last meir tinned devices avoids the neccs "tv of any nice adjustment, or positioning, of the link supports 11 (or 16); and the use of the spring-shackle form of link (Fig. is particularly advantageous in connection with certain applications of my improvements to very close built chassis frames, in which the body and axle parts are so close together that the pivot supports of the supplemental springs cannot be sufliciently offset from the longitudinal of the springs to obtain a symmetrical arcuate movement of their outer ends on the two sides of normal load position.

The organization depicted in Fig. 6 is quite similar in form to the two previously described cxeinpliiications of my invention; but as here shown this compound series spring system is arranged as a side leaf spring support for the rear axle of a motor vehicle. In this case the longitudinally disposed main spring 1 is rigidly attached, at its center, to the axle bracket or housing, 8 and is pivotally connected, at its outer extremities. to the eye ends of the two supplen'iental leaf springs 8 3 These auxiliary suspension elements are bolted at their inner ends to L-shapedlever frames 4 4"; and the latter are mounted, as before, on transverse pivots 5 5 that are considerably to one side 01": the longitudinal axes of the leaf springs 3 3". The outer ends of the levers 4L" are coupled to theiaxle bracket 8 by means of the flexibie one wvay strap connections 7", 7", which are adjustably secured to the said bracket by the clamp plates 10", 10. The pivot bolts C 5 are carried by a V-shaped frame 6 that is bolted to the body sill of the or; and the lower side of this frame may be apertured, if desired, to receive a butler block M" of rubber or other suitable material.

In the normal load position of the parts the upper edges or sides of the supplemental spring-lever units 3" 4 are in engagement with the lower face of the body sill; and the connect-ions 7 7* are adjusted until they are under a slight tension. When the system is compressed, by a kinetic increase in load, the series connected springs 1 3 -3 are increasingly flexed and concurrently flattened out, like the two sides of an ordinary full elliptic leaf spring, (as shown by the dotted lines c-c-c at the right of 6) but in this phase of the operation the connections 7 7 are inactive, and. the lever members l" 4; remain fifieil in position on the body support 6 When the body and axle parts are separated beyond normal load position-by a rebound or expansion stressthe connections 7 7 rotate the levers 4: 41-? on the oti set pivot suppo ts 5' 5 and the accelerated downward movements of the supplemental springs 3 3" relatively to the main spring! 1, tend to impose concurrently increased flexures on these series connected suspensionelements. V During this rebound movement, the bodily angular displacements of the lever-spring members, 3 l, on the offset centers of rotation, 5 o serve to maintain the eye ends of the shorter, but more severely flexed, supplemental springs in substantially fixed relation to the extremities of the longer and stifferand therefore less strongly bentmain springl and the unequally distorted elastic support members, are thus permitted to again coact, cooperate in much the same manneras the symmetrically proportioned sides of a full elliptic spring indicated by the dotted line positions R-r-r at the left of 6).

The longitudinal ri. idity of the leaf spring elements i s-3 serves to hold the axle members 2.8 in transversely centered relationship to the body parts 5 6 5 and thus prevent any endivise swaying or pitching of the tonneau on the running gear supports. In this respect also, my improved double acting combination of series connected leaf springs act like a full elliptic spring; but it is even more effective and eflicient than the latter, in resistingand preventing fore and aft movements, be-

- cause a rebound or vertical separation of the 7 body and axle members increases the flexure and therefore the longitudinal stiffness of the auxiliary springs (as well as that of the main spring 1 and also increases, to a still'greater degree, the longitudial bracing and centering action of these oppositely and symmetrically.inclined supports 3* 3".

Figs. 7, 8 and Qillustrate another utilization of my invention in conjunction With the ordinary semi-elliptic side leaf spring support for the front axle of a motor vehicle. ln'this construction the outer end of the main spring 1 is pinned, as usual, to the front horn B of the vehicle body; and the forward portion of the primary suspension member therefore acts as a radius rod to hold the axle 2 in longitudinal relationship to the tonneau frame. The shaclne links ordinarily employed to support the inner or rear end of the main spring l are removed; this end is pivotally connected to the adjacent eye of a flexible supplemental leaf spring 3, that is bolted, at its opposite extremity, to a rigid lever ira-me -l. This lever is mounted on an offset pivot bearing 5 which is carried by the body bracket 6; and is coupled, at an intermediate point in its length, to the axle frame, by means of the flexible and adjustable one-Way strap connection 7. The pintle connections for the coupled ends of the main and supplemental springs, l3, consist of flat headed male and female screws, 18l9; and these coupled ends are slidably engaged and guided by a slotted bracket 13, which is rigidly bolted to the body frame, and which may, if

desired, be transversely braced, at its lower part, by a cross bolt 20 that extends to the corresponding bracket on the opposite side of the chassis. When'the parts of thissystem are in normal load position the upper side of the frame l rests against the body sill, and the strap 7 is adjusted in lengthunder the clamp plate lO-until it has a slight initial tension. 7

The operation of this single supplemental spring suspension is essentially the same as that of the twin spring constructions previously described. V7 hen the system is subjected to akinetic increase in load the leverspring unit 34 is held in fixed relation to the body bracket- 6; and the relative approach of the axle and main spring, 2-l, toward the body frame, imposes a concurrently increased flei-Iure on the series connected springs l3, and flattens them out to the form shown in the dotted lines Cc0 of Figs. 7 and 8. When the body and axle parts are separated beyond normal load position the lever frame l is rocked in a clock- Wise direction, on its offset pivot support, 5, by the pull of the strap 7 and the suspension elements are moved from the full line position of 7 toward that shown in Fig. 8. This positive angular movement of the unitary lever-spring members, 8, produces a balanced concurrent increase in the normal tier-:ure of the series connected springs 1-3, and thus imposes a progressively and rapidly augmented resistance to any expansion of the elastic support system beyond normal load position. The primary spring 1 and the secondary lever supported spring 3 act, in this case, like very sensitive three-quarter elliptic spring unit in absorbing and checking both compression shocks and rebound stresses.

The free oscillatory movement of the inner connected ends of the spring elements (from the positions a to 0 and a to 0 respectively) is restricted to a vertical plane by the guide block 13 Which thus cooperates with the transversely rigid lever and lever support elements, l5 6, in preventing a side svvay or transverse displacement of themain spring and axle members, 12, with respect to the body of the vehicle. This slotted guide frame may also act as a stop to limit the free vertical oscillation of the concurrently flexed suspension elements and thus prevent the fr -cture or permanent distortion that might r sult from a very excessive or abnormal displacement strain. "When the connected eye ends of the spring elements come in contactivith theupper or the lower ends of the guide frame the resistance of one or the other of the elastic supports to further relative movement of the body and axle parts-is substantially increased, and the further movement of the parts in this same direction is therefore quickly and eliectively checked before the bending strain onthe springs can reach the danger point. The member 13? oi the last described construction therefore performs the same generall unctions as the correspondingly designated parts 13 or 13 or 13 of Figs. 1, 2, 3 and 4.

Figs. 10 to 13, inclusive, depict another series combination of main and supplemental springs-which embodies many of the generic characteristics of my present invention, In this combination the secondary suspension unit comprises two supplemental leat springs 8 and 3 which are bolted rigidly to: a. single lever support l that is flexibly attached to the axle bracket 6 by means of the shacklelinks 5 The inner end of the main. spring 1' is pinned to the body bracket B, and its opposite extremity is connected in series, as before, with the adjacent end of the supplemental spring 3 by means of the pintle bolts 19 -19 and the lower side bars of the vertically flexible guide link assemblage 13l3 The second auxiliary spring 3 is connected at its eye end with the body bracket 13 by the shackle connection 22. The lever support 4 is coupled to the body frame by the flexible oneway strap connection? and the adjustable clamp 10; and the cute; end of this clamp is also provided with a bearing plate 24, that is adapted to engage a roller 25 on. the adjacent extremity of the said lever, and thus hold this extremity and the attached base of the supplemental spring 3 in fixed relationship to the body when the parts are in the normal load position Nn shown in Fig. 10.

When this system is subjected to a kinetic increase in load the body and axle members are pressed toward each other, from the full line position N-n of Fig. 10 toward the positions G0c, (indicated in dotted lines in Fig. 10 and partly shown in full lines in Fig. 11) and the main and supplemental springs l 3 '3l are all subjected to balanced concurrent increases in flexural strain which serve to quickly arrest the vertical approach of the spring suspended parts. In

' this movement the base of the supplemental spring 3 is held in substantially fixed position with respect to the body of the vehicle (by the engagement of the parts 2l-25) but the connected outer ends of the main and supplemental springs, 1 -3 are permitted to move freely in a vertical plane, by the folding up of the elbow link frame 13 3, until the edges of the upper links 13 engage with the lower inset portions of the links 15 (see Fig. 11). During this movement the primary suspension elements 1 and the superimposed secondary suspension member 3 act like a three-quarter elliptic spring unit; but the auxiliary leaf spring 3? is concurrently moved away from the lower spring 1 or toward the body frame B, and is subjected to progressively increased i'lexure (as shown: in dottedlines at the left of 10) until it is ultimately broughtinto engagement, at the median portion of its length, with the said body frame.

The length 01 the strap 7 is so adjusted that this connection is preferably under a slight tension when the parts 01 the system are in static equilibrium. It, under such circumstances, the body and axle parts are separated beyond this normal position the pull of the strap 7 on the lever 4t rocks the latter in a clockwise direction on its axle support, 5 6 and this angular move.- ment again subjects the series connected springs l -"f to concurrently imposed transverse stresses that move them downwardand simultaneously increase their normal flexure and reactive resistance-until the arms, 13? 13 of the guide link frame have been straightened out (as shown in Fig. 13). and the further movement in this direction has thus been arrested. The clockwise rotation of the lever member at? also subjects the auxiliary leaf spring 3 to a progressively increased. bending strain that cooperates with the concurrently posed strains in the other two springs, 1 3 in resisting and checking the rebound or expansion out the suspension system.

The oscillatory movement of the outer ends of the springs 1 -3 within the limits above indicated-is restrained toa vertical plane by the transverse rigidity or stiffness oi": the elbow 'lrame 13 13f which thus serves the same purpose as the links or guides, 13 "139, in preventing lateral sway or transverse displacement of the any on its running gear supports. This. transverse bracing effect of the guide frame may be augmented, if desired, by extending either one of the pintle bolts, 18 or l9-as indicated at 20, Fig. 12-to the corresponding pintle element of the suspension system for the opposite side of the vehicle body..

j Vhen the series connected springs of any one of the above described organizations are strongly flexed-either by compression or expansion stresses their progressively increased elastic resistances tend to produce a violent recoil or return. of the parts to normal load position as soon as the distortion stress is removed or abated. It is desirable to. IFQShZLlD. or damp this quick recoil action, and in my present improved construction I effect this result by building up the supplemental spring elements from a relatively large number of individually thin and flexible leavesinstead of from a small number of thicker leavesand holding these leaves in close frictional engagement with each other by a plurality of spring clips such as are indicated at 15,. 15, etc. When these plural leafsprings are flexed theleaves move longitudinally with respect to each other; and the frictional engagement be tween the superimposed surfaces slows down the period of elastic oscillation, and thus retards the normally free reaction movements of the separate leaf elements. in

'order to still further augment this frictional damping restraint I may, in some cases, form the spring leaves from longitudinally corrugated strips, such as are shown in transverse cross-section in Fig. 5; thereby increasing the area of contact, and the resistance to slip, between the engaging surfaces of the flexible elements.

It will be observed, by those skilled in this art, that all of the previously considered embodiments of this invention pre-. sent, in common, a number of mechanical and functionalcharacteristics-e. g., such as have been briefly outlined in the opening considered as either delimiting, or as fully delineating, the scope of application of the present invention. v But as previously stated the special forms of construction to which this application relates exemplify only one species of a general type that is more fully described in my copending applications Ser. Nos.-400,256 and 591,708, filed July 30, 1920 and Oct. 2, 1922 respectively, and I do not, therefore, now claim the broader features of the invention as set forth in those earlier disclosures; but I do claim specifically:

1. In a spring suspension system the combination of two series-connected leaf springs interposed between the spring supported members and a one-way connection attached at one end to one of said members, and at the other end to an intermediate part of one of said springs, substantially as described.

2. In a spring suspension system for two relatively movable members the combination of a main spring attached to one member, a supplemental leaf spring pivotally supported on the other member and connected in series with one end of the said main spring, and a flexible connection secured at one end to one ofthe said members and at the other end to an intermediate part of the said supplemental spring.

3. In a spring suspension system for vehicles the combination of a plurality of seriesconnected leaf springs interposed between "the body and axle members of the vehicle lab 1,50%

and an adjustable one way connection between one of said members and an intermediate part of one of said leaf springs.

4. 111 a spring suspension system for a vehicle chassis the combination with a main leaf spring, of a supplemental leaf spring unit interposed between one end of the main spring and that part of the chassis to which said end is ordinarily attached and comprising, a secondary leaf spring, a pivot support therefor, and a one way connection between an intermediate portion thereof and an adjacent part of the vehicle chassis.

5. A spring suspension system for vehicles which comprises a main leaf spring, a secondary leaf spring connected in series with one end of the main spring, an offset pivot supported for this secondary spring, and a flexible strap attached at one end to an in- V terme-diate part of the said secondary spring and adjustably secured at the other end to one of the vertically oscillating members of the vehicle. 7

6. In a spring suspensionsystem for the body and axle members of a vehicle the combination of a main spring, a supplemental leaf spring pivotally connected at one end to the said main spring and pivotally supported at the other end on one of said members, a one-way connection between an intermediate part of said supplemental spring and the other of said members, and a guide element engaging the pivotally connected parts of the said springs and acting to resist any lateral displacement of the said parts from the plane of the system.

7. In a springsuspension system for vehicles the combination of a main leaf spring,

'a supplemental leaf spring flexibly coupled at one end to the said main spring and rigidly attached at the other end to a lever, a pivot support for the said lever which is laterally ofi'set from the longitudinal axis of the said secondary spring, and a one way connection between the said lever and one of the mutually oscillating parts of the vehicle chassis.

8. In a spring suspension system for two relatively movable members the combination ofa plurality of leaf springs flexibly coupled in series with each other, an offset pivot support for the base of one of said springs, means for holding this pivotally supported base in fixed relation to the said support when the relatively movable members are forced toward each other, and other means for rocking this same spring on the said pivot support when the said members are separated beyond the position of static equilibrium.

9. A spring suspension system for a vehicle chassis which comprises the combination of a main leaf spring, a supplemental leaf spring flexibly connected to one end of the said main spring, guide means embracing said end and acting to resist any displacement of the connected parts from the plane of the suspension system an offset pivot support for the supplemental spring, means for maintaining said supplemental spring in fixed angular relation to its pivot support when the system is subjected to compression, and a connection between one of the vertically oscillating members of the vehicle chassis and an intermediate part of the secondary spring and acting to rock the latter on its pivot support when the system rebounds or expands beyond normal load position.

10. A spring suspension system for two relatively movable members which comprises a main leaf spring, a secondary leaf spring pivotally mounted on one of said members, a collapsible one-way connection between an intermediate part of the said secondary spring and the other of said members, means for flexibly conjoining one end of the main spring to an adjacent end of the secondary spring and a guide member embracing said flexibly conjoined ends and acting both to prevent lateral displacement of the parts from the plane of the suspension system and also to limit the vertical oscillation and the fleXural distortion of the said springs.

11. A spring suspension system for vehicles which comprises a main leaf spring, a supplemental leaf spring operatively con nected in series therewith, an oflset pivotsupport for the base of the supplemental spring, a collapsible one-way connection between one of the vehicle members and an intermediate point of said supplemental spring and an elast c bufler block interposed between the relatively inelastic parts of the spring system and acting to limit the approach movement of the body and axle mem bers of. the vehicle.

12. A spring suspension system for vehicles which comprises a main leaf spring in combination with a supplemental'leaf spring connected in series therewith, means conjoining the body and axle members of the vehicle with the more rigid portions of the said springs and acting to impose progressively increased fiexures 011 the more flexible portions thereof whenever the said members are moved in either direction from normal load position; and a guide member engaging with the series connected parts of the saic springs and operating to restrain and limit the movement thereof in the plane of the sus pension system.

In testimony whereof I have hereunto set my hand.

FRANK L. O. XVADSFWORTH. 

